Aircraft and military electronic equipment is often designed to include circuit board assemblies or modules that are each formed of a plate-like metal heat sink sandwiched between a pair of circuit boards. The module is connected to a back plane or mother board through a connector system with one connector joined to an edge of the module. The connector has two rows of leads that contact two rows of terminals extending along the edges of the boards.
The connector usually must have a large number of contacts, such as more than 300, and yet the length of the connector is limited. Such a large number of contacts is accommodated by arranging them in multiple rows, such as in eight rows (i.e. four staggered rows). However, the leads extending from the contacts to the circuit boards, must lie in two parallel rows, with the leads closely spaced along the rows, such as at a spacing or pitch of 25 mil (one mil equals 0.001 inch). A reliable connector having multiple leads that extend from the multiple rows of contacts into two rows of lead rear portions, which can be constructed at moderate cost, would be of considerable value.
The plate-like heat sink can be thermally connected to a heat dissipator such as a metal cold plate, by clamping an edge of the heat sink thereto. Such clamping may displace the heat sink and module by a small but significant amount such as 10 mil. In order to avoid the need to transmit such sideward displacement through the connector to the mother board, it is desirable that an insert in the connector on which the contacts are mounted, be capable of slight lateral displacement without significant stress. A connector which enabled efficient "floating" of a connector insert would also be of considerable value.
In a connector wherein separate contacts must be attached to the front ends of leads that project from a layer of insulation formed by a wafer, it is desirable to mechanically hold each contact to the wafer in addition to its soldered or similar connection to the lead, to prevent stresses from being transmitted to the lead electrical connections. The wafer must hold the contacts precisely centered on the axes of the lead front portions, for all of a large number of such contacts. A connector which assured secure holding of each contact in a position precisely aligned with the projecting front end of each lead, would also be of considerable value.